1. Field of the Invention
This invention relates to an image projection system and, more particularly, is directed to an image projection system in which a picture produced by a television receiver is enlarged and projected for a viewer.
2. Description of the Prior Art
A conventional projector, shown in FIG. 1 and which is known as a rear projector includes a television receiver 2, a lens 3 for focusing light from the picture produced by television receiver 2, and a screen 4 onto which the picture produced by the television receiver is projected, all of the elements being arranged in series with each other in a casing 1. A viewer sees the projected picture in the direction shown by arrow A in FIG. 1. As should be clear from FIG. 1, the distance between television receiver 2 and screen 4 is considerably large, for example, the horizontal length l of the projector of FIG. 1 is about 165 cm.
Another conventional rear projector is shown in FIG. 2 to include a reflecting mirror 5, in addition to the television receiver 2, lens 3 and screen 4 in casing 1. The light from television receiver 2 is focused by lens 3, and then reflected by reflecting mirror 5 so as to be projected onto screen 4. When the magnification of the picture is the same as the projector of FIG. 1, for example, the horizontal length l of the projector of FIG. 2 is about 90 cm which is smaller than that of the projector of FIG. 1.
However, in the projector of FIG. 1, television receiver 2, lens 3 and screen 4 are arranged in series with each other, and in the projector of FIG. 2, the picture produced by television receiver 2 is reflected by reflecting mirror 5 so as to be projected onto screen 4, by the use of a certain optical law. However, the size of such projectors can not be made sufficiently small, for optical reasons.